(a) Field of the Invention
The present invention relates to a display device and a driving device thereof.
(b) Description of Related Art
A liquid crystal display (LCD) includes a pair of panels provided with pixel electrodes and a common electrode and a liquid crystal layer with dielectric anisotropy interposed between the panels. The pixel electrodes are arranged in a matrix and connected to switching elements such as thin film transistors (TFTs) such that the pixel electrodes receive image data voltages row by row. The common electrode covers the entire surface of one of the two panels and is supplied with a common voltage. A pixel electrode, a corresponding portion of the common electrode, and a corresponding portion of the liquid crystal layer form a liquid crystal capacitor. These components together with a switching element connected thereto form the basic elements of a pixel.
An LCD generates electric fields by applying voltages to pixel electrodes and a common electrode. The strength of the electric fields are varied to adjust the transmittance of light passing through the liquid crystal layer, thereby displaying images.
Recently, an LCD incorporating sensors has been developed. The sensors sense the change of pressure or incident light caused by a touch of a finger or a stylus and provide electrical signals corresponding to the detected change in pressure or light. The LCD determines whether and where a touch exists based on the electrical signals. The LCD sends the information regarding the touch to an external device. The external device may return image signals to the LCD, which are generated based on the information. Although the sensors may be provided on an external device such as a touch screen panel to be attached to the LCD, it may increase the thickness and the weight of the LCD and it may make it difficult to represent minute characters or pictures.
A sensor incorporated into an LCD may be implemented as a thin film transistor (TFT) disposed in a pixel for displaying an image. However, a reader for reading the output signals of the sensors is attached to the LCD panel, thereby increasing the size of the panel and the manufacturing cost thereof.